Process for making composite glass



Nov; 15, 1932.

J. H. SHERTS PROCESS FOR MAKING COMPOSITE GLASS Filed March 7, 1930 2 Sheets-Sheet 1 JO 6 2.9 e 519 2 32 31 F" :l. 42 WK; g

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Nov. 15, 1932. J. H. SHERTS 1,887,565

PROCESS FOR MAKING COMPOSITE GLASS I Filed March 7. 1930 2 Sheets-Sheet 2 F27 Jk 7 rGlass lmllllllllllllnll11in!!!)Illllllllnllllllllllllllll;

' I I I I I INVENTOR Patented Nov. 15, 1932 UNITED STATES PATENT OFFICE ILIFS H. SHEETS, OI BRACKENBIDGE, PENNSYLVANIA, ASSIGNOR TO DUPLATE CORPORATION, A CORPORATION OF'DELAWARE rnoonss ron MAKING oomrosrrn GLASS Application filed larch 7, 1930. Serial No. 433,944.

The invention relates to a process and apparatus for making composite glass plates and involves a development of the double pressing process and apparatus set forth 1n my application, Serial No. 380,277. The platesproduced consist in most cases of a sheet of pyroxylin plastic, such ascellulold, to the opposite side of which glass sheets are cemented. The invention has for its principal objects the provision of an improved process and apparatus in which the double pressing operation can be carried out in a single pressing apparatus instead of in two sets of apparatus, as has heretofore been proposed and without any shift of the articles between the two pressing operations, thus simplifying the operation and reducing the labor cost. Certain embodiments of the apparatus are illustrated in the accompanying drawings, wherein:

Figure 1 is a vertical section through one form of apparatus for carrying out the mvention. Fig. 2 is a section on an enlarged scale showin a part of the siackof sheets as arranged or the pressing operation. Fig. 3 is a partial section through a modification.

A. Fig. 4 is a perspective view showing a modi e ack which may be employed.

by rocking slightly during the pressing operation.

Mounted upon the table 9 is a rack for carrying the stack of plates to be composited,

such rack comprising a bottom plate 11 and a top plate 12 with telescopic securing members therebetween. These securing members each comprise a post 13 and a sleeve 14 which fits over the post. Each sleeve carries a transverse key 15 readily removable by mov.-'

top plate, the nuts 17 are loosened glli ithe keys 15 removed, after which the" plate '12 and the sleeves may be lifted upward out of the way.

. Heated liquid is supplied to the tank 1 by means of the heat exchanger18, the pipe con nections 19 and 20, andvthe circulatiiig pump 21. The pipes 19 and 20 have connection with the tank b means of the Y-pipes 22 and 23 which ta e into the tank behind the baffles 24, 24. In order to place the liquid R f i t Fi 1 1 i ti l pres=- 1-11-tlleta11k under the desired pressure,a pressure tank having a removable cover 2 and a cylinder 3 at the lower end of the tank. The cover 2 has lug portions 4 adapted to fit through slots 5 in the flange 6 at the upper edge of the tank, so that the cover may be secured in position by moving it down so that the lugs 4 lie beneath the flange 6 and then rotating the cover, the opposing surfaces of the cover and flange being provided with inclined surfaces to clamp the cover down. A gasket 7 serves to make the joint between the cover and tank tight. The cylinder 3 carries a plunger 8 upon which is mounted a table 9 and the plunger is moved up by admitting fluid under pressure to the bottom end of the cylinder through the pipe 10. A ball and socket connection 8a is provided between the upper end of the plunger and the table 9 so that the table can adjust itself a sure pump 25 is employed, which is connected to the pipe 19 and to a suppl tank 26. Provision is made for draining the tank preliminary to the pressing operation by means of a pipe 27 leading fromlthelower end of the pressure tank, such pipe being provided with a cut-off valve 28 which is closed during the pressing operation. iA

A breather pipe 29 is rovided to permit the esca e of air from t e tank when it is being fil ed with liquid, such pipe being provided with a cut-off valve 30. The tank is also provided with a vacuum pipe 31, connected to suitable exhausting apparatus and provided with a cut-off valve 31 which is closed during the pressing operation.

In preparing the sheets for laminating, they are stacked, as indicated in Fig. 2, each set of sheets comprising the lass plates 32, 32, the celluloid sheet 33,. and the layers of cement 34, 34. The cement may be of any plunger of the cylinder 3 serves to seal the desired kind, such as gelatin or casein, or joints at the edges of the composite plates it may consist of a portion of the surface of forming the stack so that when the final the celluloid sheet softened by a suitable plasrelatively high compositing pressure is apticizer or solvent, such as acetone. Where plied by the liquid in the tank, such liquid 7 a cement such as gelatin is used, it is prefwill not penetrate between the glass and the erably dried on the surface of the glass sheets celluloid sheets. After the pressure in the before stacking the plates, as indicated in t h been maintained at about 150 Fig. 2. Interposed between the plate 11 of pounds per square inch for about five minthe rack and the bottom set of plates is the utes, the pressure pump is stopped, and

sheet of copper gauze 35, and similar sheets the contents of the tank is drained through of gauze 35 are interposed between each set' the pipe 27, the valve 30 in the breather pipe of sheets and between the top plate 12 of the g pen d at hi time in order to farack. The purpose ofthese gauze sheets is cilitate the drainage. The cover 2 is then 1 to cushion the glass sheets and reduce any moved and the table 11 moved up, thus tendency towards breakage and also to permoving the rack through the top of the tank. mit a circulation of hot liquid between the e k can then be removed, the,plate 12 sets of sheets during the final pressing operataken off and the composited plates removed tion, as later described, this being necessary m h table 1, h s complet ng the cycle. in order to heat the stack of plates with sufii- Water may be used as a pressing l quid in cient rapidity and also to render such heating he tank 1, but a high boiling pyroxyhn plasunif th h t th t k Aft th tic solvent is preferred, such as diethyl glycol stack of sheets is assembled upon the bottom l yl phthalate.

plate 11 of the rack, the top plate 12 is placed Fig. 3 illustrates a modification in which in positio thereover7 th k 15 ar inthe rack of the Fig. 1 construction is omitted, serted, and th t 17 a screwed up t the plates being pressed directly between the clamp the stack of lates lightly between COVeI 2 Of the tank and the table lcarried by th two lat 11 112, th ti g the plunger. In other respects, this construcany movement of the sheets upon each other 0 s e sa e as that of Fig. 1. In using during th mo t of th a k fro the this apparatus, the sets of sheets are assempoint of assembly to th tank 1, Wh n th bled directly upon the table 9, such table berack with assembled sheets therein is brought 111g p shed up by Its plunger so that it lies to the tank, the table 9 is moved up by its above the top of the tank. After the assemplunger to the upper end of the tank and blmg operation, the table is lowered into the the rack is placed upon such table. The tank, the cover 2 applied, and fluid is adtable is then lowered to the position indimltted to the pressure cylinder 3 to move the cated in Fig. 1, and the cover 2 is applied. table up so that the sets of sheets are placed I g Q 0 0 the plungeLin 11ndeLcompression between the table and the the cylinder '3 to place the stack of sheets cover. In carrying out this operation, the 4;) under compression, such pressure being in the gauze sheets 35 are employed the same as in 1 neighborhood of 60 pounds per square inch the apparatus of Fig. 1. 7 between the opposing surfaces of the sheets Flg. 4 illustrates a modified form of rack constituting the stack. At the same-time, the which may be employed for carrying the air in the tank is exhausted through the sheets to and from the pressing tank in place 45 vacuum pipe '30 which exhaustion step proof the rack of Fig. 1. This rack consists of motes the escape of any air which may be a bottom plate 36 on which the sets of sheets entrapped between the glass and celluloid ar tacked for compositing. Plates 37, 37 sheets, the valve 31 is closed and hepnnmg tfwlded to the ends of the plate 36 and pro- I 25 and 21 are QPBESXQdtO' fill e tank 1 and Vided with the perforations 38, 38 by means n. con inuet e circulation of fluid therethrough of which the rack and its contents may be 11 until the desired temperature is reached. a r frOIn n overhead Crane. This rack Such temperature is in the neighborhood of with its contents 1s placed upon the table 9 235 degrees F. It is desired to bring the tem- 1n the p s 9 the Fig; 1 Construction and 'peratu f th ll l id h t t a i t the compos1tingoperat1on is carried out as 55 where th material i li htl la ti hi h heretofore descr bed, the rack serving as the occurs at about 200 degrees F., and in order means for carrying the stack of sheets to be to accomplish this more rapidly, a temperacomposited to and from thetank. ture in the liquid is employed which is in What I claim is: ex e of 200 degrees F, A th li id b A process of compositing a series of sets (:0 comes heated, the pressure pump 25 is opof sheets, each comprising a pair of glass v 'erated to bring the pressure in the tank up sheets with an interposed sheet of pyroxylin to about 150 pounds per square inch. lhis plastic and layers of cement, which consists pressure gives the final pressing operation in superposing such sheets in a stack one upon the sets of sheets. The preliminary above the other in a pressure chamber with 65 pressing operation as accomplished by the their edges exposed, exhausting the air from Gil the chamber and applying pressure to the stack of sheets so as to press the opposing surfaces thereof tightly together, then ad mitting heated liquid to the chamber to soften the plastic sheets slightly while the pressure on said sheets is maintained, and finally applying pressure to said liquid to increase the pressure between the opposing surfaces of the sheets.

In testimony whereof, I have hereunto subscribed my name this first day of March, 1930.

JAMES H. SHEETS. 

